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Chemically enhanced autoignition in a spark-ignited engine with a special design of piston geometry has been observed experimentally, in which the engine would operate stably without a spark, once it is started by spark ignition. Under this operation mode, the engine provides lower pollutant emissions including NOx. In this process, the intermediate species left from the previous cycle play a key role in the low temperature autoignition. The objective of this study is to determine the effect of some important radical and intermediate species, such as HO2, OH, and H2O2, on autoignition by a numerical modeling approach using a detailed chemical kinetic mechanism. The fuel studied is hydrogen. The effect of added HO2, OH and H2O2 on the characteristics of the autoignition of H2-air mixture is investigated. Chemically enhanced autoignition of H2-air in an internal combustion engine is also simulated.

The 1990 Clean Air Act Amendments, the Energy Policy Act of 1992, and Executive Order 12759 have provided a significant boost to plans for the development and use of alternative fuels and alternative fuel vehicles (AFVs). While the federal initiatives require the use of substantial numbers of alternative fuel vehicles nationwide in both government and private fleets, there is still a great deal to learn about the development, maturation, and use of alternative fuels and vehicles-vehicle durability, reliability and performance, fuel composition and purity requirements, emission characteristics, fuel availability and storage, and a host of other technology and infrastructure issues. There is a need and an opportunity to identify and prioritize the short-term and long-term technology and human factors issues to be addressed.

Addition of hydrogen-rich gas to gasoline in internal combustion engines is gaining increasing interest, as it seems suitable to reach near-zero emission combustion, able to easily meet future stringent regulations. Bottled gas was used to simulate the output of an on-board reformer (21%H2, 24%CO, 55%N2). Measurements were carried out on a 4-stroke, 2-cylinder, 0.5-liter engine, with EGR, in order to calculate the heat release rate through a detailed two-zone model. A quasi-dimensional model of the flame was developed: it consists of a geometrical estimate of the flame surface, which is then coupled with the heat release rate. The turbulent flame speed can then be inferred. The model was then applied to blends of gasoline with hydrogen-rich gas, showing the effect on the flame speed and transition from laminar to turbulent combustion.

As a future sustainable fuel, hydrogen will significantly reduce reliance on fossil energy resources as well as the amount of exhaust emitted by automobiles. It is a carbon-free fuel, and it can be produced through a number of conversion technologies, including thermochemical, electrochemical, and biological processes. However, with advanced PEM fuel cell technologies to drive commercialization and commercial vehicle growth, hydrogen fuel quality for efficient fuel cell system performance, and fuel storage system product design with all safety features are the unique selling points. Though the concept of the hydrogen storage system for fuel cell electric vehicles (FCEV) is derived from global technologies, it cannot be implemented directly in the Indian CV (commercial vehicle) market. A certain level of technology can only be transmitted.

In today’s world, fuel injection technology is vital in the development of vehicles powered by gaseous fuel to achieve United Nation’s Sustainable Development Goal (SDG) Affordable and Clean Energy, as energy is the enabler of all other SDGs. There is a definite scope of gaseous injectors for development and testing of H2 engine. This paper describes the procedures to select injectors for handling hydrogen fuels in SI engines and the suitability of compressed natural gas (CNG) injector for using hydrogen fuel. The selection of injectors for introducing gaseous fuel depends on the parameters such as duty cycle and pulse width of the injector. The calculation for injector pulse width and injector flow/spray for determining the engine performance also discussed. The final calculated results are validated with experimental results, as well as engine performance parameters, which are within 10 % of the calculated results.

Hydrogen-rich fuels, via lean operating ability, potentially offer both emission control opportunities and engine efficiency gains not possible with gasoline. With a single-cylinder engine, the emission characteristics of two types of hydrogen-rich fuels were evaluated. The first fuel contained various proportions of hydrogen and gasoline. The test objective was to determine whether increasing HEF, the fraction of total fuel energy supplied by hydrogen, would significantly reduce HC emission at ultra-lean conditions. While holding NOx emission comparable to a 0.4 g/mile equivalent, HC emission was reduced 50 percent by increasing HEF from 0.13 to 0.48. However, even with this maximum practical level of hydrogen enrichment, the resulting HC emission was not significantly different than values obtained with richer mixtures of gasoline and still far in excess of a 0.41 g/mile equivalent. Therefore, hydrogen enrichment does not appear to be a sufficient means of reducing HC emission.

Hydrogen gas, H2, is the environmentally desirable fuel of choice for powering fuel cells and internal combustion engines. However, hydrogen is extremely difficult to store, handle, and transport. One major hurdle to commercializing hydrogen-powered vehicles is providing a way to effectively and safely generate, store, and deliver the large amounts of H2 needed to achieve acceptable vehicle range while minimizing the weight and volume of the storage system. Millennium Cell has developed a novel catalytic process that generates high purity H2 gas from air-stable, non-flammable, hydrogen-rich water-based solutions of sodium borohydride, NaBH4. This on-board system has already been used by Millennium Cell to successfully power a hydrogen powered series-hybrid sport utility vehicle [1], a full size six-passenger sedan with an internal combustion engine running on hydrogen gas, and is currently being installed into a fuel cell vehicle.

An investigation has been done on the influence of small amounts of hydrogen added to hydrocarbons-air mixtures on combustion characteristics. The effect of hydrogen addition to a hydrocarbon-air mixture was firstly approached in an experimental bomb, to measure the laminar burning velocity and the shift of lean flammability limit. Experiments carried out with a single-cylinder four stroke SI engine confirmed the possibility of expanding the combustion stability limit, which correlates well with the general trend of enhancing the rate of combustion. An increase of brake thermal efficiency has been obtained with a reduction of HC emissions; the NOx emissions were higher, except for very lean mixtures.

In this study, characteristics of the development and auto-ignition/combustion of hydrogen jets were investigated in a constant-volume vessel. The authors focused on the effects of the jet developing process and thermodynamic states of the ambient gas on auto-ignition delays of hydrogen jets. The results show that the ambient gas temperature and nozzle-hole diameter are significantly effective parameters. By contrast, it is clarified that the ambient gas oxygen concentration has a weak effect on the auto-ignition/combustion of hydrogen jets. Consequently, it is supposed that the mixture formation process is capable of improving the auto-ignition/combustion of hydrogen jets.

The combustion characteristics of three gaseous fuels (hydrogen, methane and ethane) in a direct-injection stratified-charge single-cylinder engine with a centered square head-cup operated at 800 rpm (compression ratio = 10.8, squish ratio = 75%, nominal swirl ratio = 4) were studied to assess the extent to which the combustion is controlled by turbulent mixing, laminar mixing and chemical kinetics. The injection of gaseous fuels was via a Ford AFI injector, originally designed for the air-forced injection of liquid fuel. Pressure measurements in the engine cylinder and in the injector body, coupled with optical measurements of the injector poppet lift and shadowgraph images of the fuel jets provided both quantitative and qualitative information about the in-cylinder processes. To make the cases comparable, the total momentum of the fuel jets and the total heat released by the three fuels was kept the same (equivalence ratio = 0.316, 0.363, 0.329 for H2, CH4 and C2H6, respectively).

NOx are the only harmful emissions of hydrogen internal combustion engine. EGR is one of the effective methods to reduce NOx. The traditional EGR is not suitable for hydrogen internal combustion engine. Therefore, the study of influence of hot EGR on hydrogen internal combustion engine is important. A 2.0L hydrogen internal combustion engine with hot EGR system model is employed to optimize the diameter and position of hot EGR based on a simulation analysis. The result shows that both of the combustion temperature and NOx increase as EGR increases due to the rise of intake temperature for low load condition, for heavy load, with the increase of EGR rate, NOx emissions decreases slightly before the mixture equivalence ratio comes to 1and then dropped significantly after the mixture equivalence ratio greater than 1. Unburned hydrogen in TWC has the effect of reducing NOx after catalysts decrease largely.

Nowadays, the world is facing severe energy crisis and environment problems. Development of hydrogen fuel vehicles is one of the best ways to solve these problems. Due to the difficulties of infrastructures, such as the hydrogen transport and storage, hydrogen fuel vehicles have not been widely used yet. As a result, Hydrogen-gasoline dual-fuel vehicle is a solution as a compromise. In this paper, three way catalytic converter (TWC) was used to reduce emissions of hydrogen-gasoline dual-fuel vehicles. On wide open throttle and load characteristics, the conversion efficiency of TWC in gasoline engine was measured. Then the TWC was connected to a hydrogen internal combustion engine. After switching the hydrogen and gasoline working mode, emission data was measured. Experiment results show that the efficiency of a traditional TWC can be maintained above 85%., while it works in a hydrogen-gasoline dual-fuel alternative working mode.

Studies of emissions from vehicles equipped with catalysts have shown that some unregulated emissions can increase when a catalyst is used. One example of this is sulfuric acid, which has been studied extensively. Other unregulated emissions include ammonia and hydrogen cyanide. In a number of studies, these unregulated pollutant emissions have been measured from light-duty vehicles and heavy-duty engines. These emission levels were used in air quality dispersion models to predict the resultant air quality levels. The ambient concentrations predicted for each pollutant were then compared to suggested concentrations at which adverse health effects may be found to determine if additional monitoring or control would be indicated for these pollutants. It was determined that mobile source emissions of sulfuric acid, hydrogen cyanide, and ammonia do not in general result in ambient levels of concern for the air quality situations studied.

A fundamental understanding of the relationship between chemical composition and combustion quality may provide an improved means of assessing fuel combustion characteristics. As such, a fuel parameter based on the average molecular structure of multi-component fuels, including petroleum-derived fuels and alternative fuels such as bio-fuel, is applied to predict both ignition and anti-knock quality. This parameter is derived from proton nuclear magnetic resonance (1H-NMR) analysis indicating hydrogen type distribution of fuel molecules. The predicted cetane number (PCN) calculated by the equation developed with 1H-NMR in this study shows a good correlation to the cetane number for a wide range of fuels.

Hydrogen generation by water electrolysis was carried out using solar cells. As the electrolyte, sulfuric acid solution was used. As a reference, a single electrolyte cell of solid polymer membrane was used too. Mono- and poly-crystalline silicon solar cells were employed. The output of solar cells was connected to the electrolytic electrodes directly. The conversion efficiency of solar energy to generated hydrogen energy was evaluated. The hydrogen production for one year was estimated on the base of measured data of solar radiation, and the effect of reduction of CO2 production by exchanging fossil fuels (LPG and Town gas) with hydrogen was evaluated.

Natural Gas is one of the abundant fuel available on the earth and considered as a one of the cleanest fossil fuels. Most of the studies are conducted on CNG with different blends of hydrogen to improve the efficiency of engine and reduce the emission. However, components safety and its compatibility to these fuels were not studied in depth. Project was taken to understand material compatibility of CNG kit components and framing the National standards which can also be used for providing the inputs to international standards like ISO, ECE etc. Various components have been selected a sample base from CNG fuel kit for this study such as Refilling Valve, High Pressure Regulator and Gas Solenoid Valve, Rigid Pipe, low pressure flexible hose, etc. from renowned manufactures in the country and around the globe.

Rubber O-rings installed in hydrogen tanks for fuel cell electric vehicles are repeatedly exposed to high pressure hydrogen gas. Exposure to high pressure gas sometimes causes cracks as a result of blistering after decompression. The degree of blister damage is influenced by material, environmental conditions such as decompression rate, and sealing shape such as squeeze ratio. Focusing on environmental conditions out of these influential factors, in this study, a high pressure hydrogen durability tester which exposes rubber O-rings repeatedly to high pressure hydrogen gas at arbitrary test conditions was developed. Using this tester, the influence of hydrogen pressure and temperature on blister damage and permeability was investigated for sealing materials used conventionally for high pressure equipment.

Global warming caused by greenhouse gases are currently a significant problem in the world. Hydrogen is regarded as one of the possible sources of energy for the future. Hydrogen fueled engines emit no carbon dioxide as tank-to-wheel. Hydrogen engines can reduce greenhouse gases in comparison to engines fueled with fossil fuels. A pre-mixed hydrogen-fueled engine, specifically, can be put into practical use in a short period of time from a technical point of view. However, there are some technical issues, such as backfiring and low power output to resolve. With the aim to put a pre-mixed hydrogen-fueled engine for trucks and buses into practical use, it is necessary to prevent backfiring and to develop a high output engine. A diesel engine modified as a pre-mixed hydrogen-fueled engine was equipped with a variable geometry turbo-charger for higher output.

The subject of this study is a centrifugal compressor for Fuel Cell Electric Vehicles (FCEV). Recently there is a growing interest in FCEVs since they are considered a realistic solution to environmental regulations for passenger cars to reduce emissions. Water vapor is the only byproduct of a reaction in the Proton Electrolyte Membrane (PEM) fuel cell stack which generates electricity with oxygen from the surrounding air and hydrogen from a fuel tank. Auxiliary systems called Balance of Plant (BOP) serve to provide air and hydrogen to the stack in a correct ratio. The compressor is one of key components of this system because compression of the intake air brings an increase in efficiency and power density of the FCEV. This paper presents the characteristics of a 10 kW class centrifugal compressor with an oil-free bearing system. It consists of a shaft, two airfoil journal bearings and a pair of thrust bearings.

It is a well-known fact that the exhaust emission characteristics of hydrogen fueled engines are extremely good. The external mixture formation - a hydrogen fuel supply method - has the merit of practically zero NOx emission level in the lean mixture range with the excess air ratio λ set at 2.0 or greater as well as the merits of simple mechanism and easy operation. However, the practical use of such engines has been impeded partly due to the occurrence of backfire where the excess air ratio λ is 2 to 3. In order to allow the practical use of the hydrogen fueled engines with external mixture formation, it is vital to determine the causes of backfire and to establish proper countermeasures. It is found through a recent study conducted on the mechanism of backfire that the abnormal electric discharge in the intake stroke is one of the causes of backfire.